Colin Jacobs wrote:
Oh, I know that ! I have been an allotment holder for 23 years and have just
taken this one on due to moving house.
I relish a challenge but getting it out an easy way is a much better
challenge too.
Thanks for all the advice
Brush cutter, spray, then digging them out seems the best method.
[...]

I don't think I've ever sprayed brambles*, and I've dealt with some
very nasty infestations. Cut them off near the base, and the crowns are
shallow-rooted and will generally come out pretty easily, especially if
the soil's in the excellent condition you may well find after they've
been undisturbed for fifty years. On loosish soil, a strong rake is a
good tool for the job, as you don't have top bend: whack it in, twist
slightly, and haul out. Roots left behind won't regrow: only bits of
crown can do that. There will be seedlings, of course; but spraying the
parent plants won't help you with that.

*Though I have spot-treated ones which have matured among desirable
plants: chop off, allow shoots to appear, treat. I've even used a
water-colour brush to put SBK on cut ends, but I don't think people
should generally be handling that kind of thing.

--
Mike.